The invention relates to an apparatus for supplying power to a motor vehicle, in particular a passenger vehicle or motorcycle. The apparatus has a plurality of electrochemical storage cells and/or double-layer capacitors.
Known electrochemical storage cells are cooled from the exterior, i.e., their jackets are cooled. This is complicated, and sufficient cooling cannot always be reliably ensured. As a result, defects suddenly occur, which are not economically compatible with the service life requirements in automobiles.
The object of the invention is to provide a reliable apparatus for supplying power, in particular for the intermittent electric motor drive of a motor vehicle (hybrid vehicle).
This object is achieved by an apparatus for supplying power to a motor vehicle, in particular a passenger vehicle or motorcycle, the apparatus having a plurality of electrochemical storage cells and/or double-layer capacitors. At least one of the electrodes respectively situated in the storage cells and/or double-layer capacitors is made of metal or is provided with a metal layer essentially over its entire surface. The metal electrode or the metal layer, in particular a metal foil, is connected in an electrically conductive manner via a connecting element to a terminal provided outside the storage cell or outside the double-layer capacitor. A thermally conductive cooling plate is in thermal contact with essentially each of the terminals of the storage cells or double-layer capacitors. The cooling plate dissipates the thermal energy, which is supplied by the metal electrodes or the metal layers on the electrodes, to the terminal via the connecting element. Advantageous embodiments of the invention are described herein.
The invention provides for the refinement of a known apparatus for supplying power to a motor vehicle, in particular a passenger vehicle or motorcycle, the apparatus having a plurality of electrochemical storage cells and/or double-layer capacitors, wherein at least one of the electrodes respectively situated in the storage cells is made of metal or is provided with a metal layer essentially over its entire surface. The metal electrode or the metal layer, in particular a metal foil, is connected in an electrically conductive manner via a connecting element to a terminal provided outside the storage cell or outside the double-layer capacitor.
According to the invention, a thermally conductive cooling plate, which is in thermal contact with a plurality of the terminals of the storage cells or the double-layer capacitors, dissipates the thermal energy which is supplied by the metal electrodes or the metal layers on the electrodes to the terminal via the connecting element. Instead of cooling at all the terminals, it is also possible, for example, to perform one-sided cooling of the storage cells at the terminals, on the affected side of the storage cells or double-layer capacitors, whereby the terminals on the opposite side remain uncooled if this is sufficient.
In this manner, the heat may advantageously be reliably dissipated directly at the site of origin, even for use in an automobile. The design complexity is relatively low, and the apparatus according to the invention is characterized by a long service life.
The electrochemical storage cells are, preferably, lithium-ion batteries or barium titanate capacitors, which are characterized by high storage capacity and low volume.
The invention provides for the use of electrochemical storage cells, double-layer capacitors, or a combination thereof. The storage cells or double-layer capacitors in each case have a circular, prismatic, rectangular or square, oval, or flattened oval cross section, or have a flat-cell design in the form of a “coffee bag.” Depending on the requirements, modules may be produced from storage cells or double-layer capacitors which have a high packing density without cavities, or which have fairly large cavities between the storage cells or double-layer capacitors. The modules may be, for example, actively cooled using a cooling medium which is passed through, or for passive cooling, cooled by means of thermal convection.
In one embodiment of the invention, the cooling plate contains a thermally conductive material, in particular metal. An electrically insulating, thermally conductive layer is provided between the cooling plate and the terminals. In this manner, satisfactory cooling may be achieved without the risk of short circuits.
In one refinement of the invention, the thermally conductive layer is formed from one or more superposed heat-conducting foils composed in particular of polyimide or thin PTFE. It is preferred to use one or more foils having an overall thickness of preferably 0.05 mm. When two or more superposed heat-conducting foils are used, the possibility that even a locally limited material defect in any of the heat-conducting foils is located directly above the other material defect may be excluded with a high degree of certainty. In this manner, electrical short circuits resulting from material defects, which can never be excluded, may be effectively prevented.
In one embodiment of the invention, the first side of the heat-conducting foil is fixed to the terminals, preferably by gluing. The second side has a slide coating, in particular a PVDF or PTFE coating. On the one hand, the position of the heat-conducting foil is spatially fixed, and on the other hand the heat-conducting foil is able to slide over the thermal contact surface for the cooling plate, so that the heat-conducting foil is not damaged, even when there are vibrations or relative motions between the storage cell or double-layer capacitor and the cooling plate. In this manner, the reliability of the apparatus according to the invention is further increased, and short circuits are effectively avoided.
In one refinement of the invention a heat-conducting foil, which is plastically or elastically deformable under pressure, is provided between the terminals of the storage cells and the cooling plate. According to the invention, such a heat-conducting foil is preferably electrically insulating, and preferably compensates for production tolerances in the distance; i.e., the heat-conducting foil fills gaps. In this manner good thermal contact is achieved, even for customary production tolerances and in the presence of vibrations. Such a heat-conducting foil preferably contains ceramic, silicone, wax, or a mixture of various thermally conductive substrates, and may have multilayer coatings.
In one embodiment of the invention the cooling plate is provided with a plurality of thermally conductive spring elements. Each of the spring elements thermally contacts a terminal of the storage cells via the thermally conductive layer. The heat at the cooling plate is dissipated via the spring elements. This measure allows good thermal contact even for customary production tolerances, which result in variation of the distance between the storage cell and the cooling plate. Interruption of the thermally conductive connection as the result of vibrations is likewise effectively prevented.
In one refinement of the invention, the cooling plate has cooling channels through or around which a heat-dissipating medium, in particular a refrigerant such as R 134a or carbon dioxide R 744, water, or air, flows. In this manner, the heat dissipation may consistently and reliably be ensured to a sufficient degree, even during intermittent peak loads on the storage cell.
In one embodiment of the invention multiple cooling plates are consecutively positioned at a distance from one another. Multiple storage cells or double-layer capacitors are provided between the covers of every two adjacent cooling plates. In this manner, a compact design is achieved.
In one embodiment of the invention, the storage cells or double-layer capacitors between two adjacent cooling plates are provided in the form of multiple modules of storage cells connected in series, in each case the maximum contact voltage of the modules being less than 60 volts.
In one refinement of the invention a housing cover is provided. The housing cover has electrical connectors which connect the modules between the two adjacent cooling plates in series when the modules are covered by the housing cover and which interrupt the series connection when the housing cover is removed.
The above measures prevent contact by a hazardous contact voltage without reducing the compactness of the apparatus according to the invention.
In one embodiment of the invention, at least some of the lateral surfaces of the cooling plates are brought into essentially perpendicular contact with a first and a second cooling wall, which extends over multiple consecutively positioned storage cells or double-layer capacitors. The storage cells or double-layer capacitors are situated between the first and the second cooling wall. In this manner, the storage cells or double-layer capacitors are housed compactly with good mechanical protection.
In one embodiment of the invention, the first or the second cooling wall is provided with cooling channels, which are connected to the cooling channels in the cooling plates. In this manner, a high degree of heat dissipation is achieved with compact dimensions of the apparatus according to the invention.
In one embodiment of the invention, the connecting elements for the storage cells or double-layer capacitors are electrically connected to one another via electrical connectors such that the storage cells or double-layer capacitors are connected in series. The electrical connectors are preferably dimensioned so that they greatly increase the thermal contact surface with the thermally conductive layer in comparison to the connecting elements alone. The connectors are preferably strips, cables, or flexible leads, which are welded or soldered to the connecting elements. Heat dissipation may be improved considerably by use of these structural measures, which have a simple design and are economically implemented.
In one exemplary embodiment of the invention, printed circuit boards containing printed conductors are provided between the electrical connectors. The printed conductors electrically contact the connecting elements of each storage cell, and tap the voltage present at each of the storage cells or double-layer capacitors, the current flow, or another characteristic parameter of the storage cell such as electric capacity or capacitance. To increase the service life, the characteristic parameter or voltage is supplied to a control device, which balances or compensates for the energy content of the storage cells or double-layer capacitors relative to one another.
In one embodiment of the invention the storage cells or double-layer capacitors, the cooling plates, and optionally the cooling walls are enclosed by thermal insulation. In one embodiment of the invention, one or more of the cooling plates and/or the cooling walls are provided with an air conditioner device, preferably electrically operated, which dissipates the thermal energy and preferably operates according to the evaporative or Peltier process.
In this manner, the apparatus according to the invention may be reliably cooled with little expenditure of effort, uninfluenced by the surrounding temperature at the specific location in the vehicle where the apparatus according to the invention is provided.
The invention is explained below with reference to drawings, which are not necessarily to scale. Identical or functionally equivalent parts are designated by the same reference numerals.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.